Method and apparatus for making wrought metal branch fittings



Filed Sept. 12, 1966 y 1969 R. A. GRAY, JR.. ET AL METHOD AND APPARATUS FOR MAKING WROUGHT METAL BRANCH FITTINGS Sheet 2255 gjgirvfrolw.

May 6, 1969 R. A. GRAY, JR. ET AL 3,442,106

7 METHOD AND APPARATUS FOR MAKING WROUGHT METAL BRANCH FITTINGS Filed Sept. 12. 1966 Sheet 3 or 2 OW/ME/S.

United States Patent 3,442,106 METHOD AND APPARATUS FOR MAKING WROUGHT METAL BRANCH FITTINGS Robert A. Gray, Jr., and James F. Shuler, Port Huron, Mich., assignors to Mueller Brass (10., Port Huron, Mich., a corporation of Michigan Filed Sept. 12, 1966, Ser. No. 583,134 Int. Cl. B21d 39/08, 53/00; B2lk 29/00 U.S. Cl. 72-58 2 Claims ABSTRACT OF THE DISCLOSURE A die has main cavity and a branch cavity. A tubular blank is placed in the main cavity and male and female rams engage the blank ends. The male rarn has a reduced portion extending through the blank and into the female ram, and a fluid passage in the male ram conducts fluid pressure to the vicinity of the branch cavity.

This invention relates to the manufacture of wrought metal branch fittings. The phrase branch fittings in this specification and the appended claims is meant to include pipe fittings of various types such as Ts, crosses and other fittings having lateral branches for connection to pipes, whether the several outlets be of the same or different sizes.

The manufacture of wrought metal branch fittings by deforming tubular stock has taken two basic forms, one of which is the combined application of mechanical end pressure and internal hydraulic pressure on the tube, and the other being the use of a fusible and deformable alloy within the tube combined with mechanical end pressure. The combined mechanical pressure and fluid method is exemplified by Gray et al. Patent No. 2,203,868 issued June 11, 1940, while the combined mechanical pressure and fusible metal method is shown in Seeber et al. Patent No. 2,111,695 and Arbogast Patent No. 2,557,403. In either case, a die surrounds the tubular blank and is provided with a radial cavity into which a portion of the material of the tubular blank is forced so as to define a branch.

One major problem which is present in both of these methods is the build up of metal at the central portion of the fitting due to the forcing of the ends toward the center. This has necessitated the internal machining of the fitting after manufacture in order to enlarge the internal diameter to the required size and reduce flow interference. Thus, not only is metal wasted but a costly manufacturing process results.

A modified form of the combined mechanical pressure and fusible metal method is shown in Heuss et al. Patent No. 2,975,510, in which pressure in the final stages is exerted only in the fusiblemetal and not on the tubular blank. However, this has been found to result in excessive thinning of the metal wall thickness at the central portion of the fitting. In order to manufacture an acceptable branch fitting with the method of Heuss et al., it is necessary to provide an initial wall thickness which is substantially greater than that needed with other known methods. Thus, this method has the drawback of other conventional methods in that excessive metal is needed, and in the case of copper fittings for example, this could mean substantially greater expense.

It is an object of the present invention to provide a novel and improved method and apparatus for the manu- 3,442,106 Patented May 6, 1969 facture of wrought metal branch fittings which overcomes the above described disadvantages of previously known methods and permits the manufacture of a seamless branch fitting without excessive metal being used and without the need for subsequent machining operations or fusible metal in order to obtain the required inside diameter for proper flow characteristics in the run of the fitting.

It is another object to provide an improved apparatus of this nature which permits the use of initial tubular stock with the minimum inside diameter required to be in conformance with control standards, thus having a minimum weight in the final branch fitting.

It is a further object to provide an improved method and apparatus having these characteristics, in which lapping or folding of the metal at the central portion of the tubular blank is prevented.

It is another object to provide a novel method and apparatus of this type which permits various kinds of stops and solder cups to be formed in the branch fitting for the pipe ends, and which further permits the inside diameter of the branch fitting to be used as a piloting diameter for a sizing tool in forming the solder cups.

Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a partially schematic cross-section view showing the tubular blank in position between the telescoping rams of the invention, ready to be deformed;

FIGURE 2 is a view similar to FIGURE 1 but showing the blank in partially deformed position;

FIGURE 3 is a view similar to FIGURES l and 2 but showing the blank in the fully deformed position;

FIGURE 4 is a cross-sectional view taken along the line 44 of FIGURE 3, and showing the cross-sectional configuration of the wall at the central portion of the branch fitting;

FIGURE 5 is a view of the completely deformed blank, similar to that of FIGURE 3 but showing the cap of the branch removed, and

FIGURE 6 is a view similar to FIGURE 5 but showing the manner in which solder cups could be formed in the sockets of the branch fitting by sizing the end diameters.

Briefly, the illustrated embodiment of the invention is centered around the use of two telescoping ram elements which engage opposite ends of the tubular blank and force these ends toward each other as the blank is confined within a die having a lateral cavity to receive the branch being formed. From the very beginning of the deforming operation, one of the rams, the male element, is telescopically received by the female ram element, so that the run of the fitting is always confined within the annular space between the male ram element and the die. The male ram element has a shoulder which engages one end of the tubular blank and the end of the female ram element engages the other end. The male ram element also has a fluid passage extending axially therethrough, with a lateral end passage in the area of the branch cavity of the die. Fluid under pressure is applied through these passages while the ends of the blank are being forced together, to cause the metal to flow into the branch cavity of the die. After the deformation is complete, the blank is taken from the die and the end of the branch is cut off to form the fitting.

Since the male ram element is at all times disposed within the run of the tubular blank as it is formed into a branch fitting, there will be no thickening, lapping or folding of the metal in the central portion of the branch fitting. The metal will substantially retain its original inside diameter throughout the run of the fitting, and there will be no constriction formed therein which would hamper fluid flow.

Referring more particularly to the drawings, the die is generally indicated at 11 and comprises an upper half 12 and a lower half 13. Each half of the die may be formed of a block of steel, and the facing surfaces of the two die elements have aligned semi-cylindrical grooves 14 and 15 which together form a cylindrical cavity indicated generally at 16. Upper die 12 has an upwardly extending recess 17 which is circular in shape and is intended to receive the extruded portions of a tubular blank 18 during the branch forming operation. The diameter of recess 17 is so chosen as to create the proper diameter for the branch, and a radius 19 is formed between recess 17 and main cavity 16. A vent opening 21 is provided at the top of cavity 17 for permitting air removal during operation.

The ram is generally indicated at 22 and has two parts, a male element 23 and a female element 24. Male element 23 has a main section of cylindrical shape which is slidable within cavity 16, and a reduced section 25 at the outer end thereof, a shoulder 26 being formed between the main section and section 25. The radial width of shoulder 26 is roughly equal to the wall thickness of tubular blank 18, so that section 25 is slidable within the tubular blank. The outer end of ram element 23 is provided with a connection 27 for attachment to a source of pressurized fluid, and a central passage 28 is provided in element 23 leading from this connection to an intermediate portion of section 25 thereof. A radial branch 29 leads from this end of passage 28 to the surface of ram section 25.

Female ram element 24 has a main portion which is of constant outside diameter, the diameter being such that this ram element is slidable within cavity 16. A shoulder 30 at the end of element 24 is engageable with tubular blank 18. The internal diameter 31 of the outer portion of ram element 24 is such that portion 25 of ram element 23 is slidable therein. This portion of ram element 24 is of suflicient length to accommodate section 25 of ram element 23 as it penetrates ram element 24 during the branch forming operation. A passage 32 leads from bore 31 toward the other end of the female ram element for permitting air to escape from bore 31. The outer ends of ram elements 23 and 24 have means 33 and 34 respectively, for connecting these elements with a force exerting apparatus (not shown) so that the ram elements may be forced toward each other during the operation.

The tubular blank 18 may be made of any extrudable, malleable material such as copper which is to be formed into the branch fitting. Although the principles of this invention are applicable to various sizes and shapes of tubular blanks, a preferable manner of carrying out the invention would be to choose the inside diameter of tubular blank 18 as that prescribed by appropriate standards for the use to which the branch fitting is to be put. For example, standards such as the ASA B16, 224963 Standard for Wrought Copper and Bronze Solder-Joint Pressure Fittings require the inside diameter of the fitting to be above a specified minimum to prevent undue constriction of fluid flow. The tubular stock from which blank 18 is cut could have this inside diameter, since the forming method of this invention will not reduce the inside diameter any further. Thus, a minimum weight stock could be used to manufacture any particular branch fitting.

The original length of tubular blank 18 is of course much greater than its final length, and the length of ram 4 section 25 is such that it is greater than the original length of blank 18.

In carrying out the invention, tubular blank 18 will be placed in an intermediate portion of cavity 16, being centered on cavity 17 if the branch is to be centered in the final fitting. Male ram section 25 is inserted in blank 18 until shoulder 26 engages the right hand end of the blank in FIGURE 1. Female ram element 24 is inserted in cavity 16 until end 30 thereof engages the left hand end of the blank.

The two ram elements are then moved toward each other with considerable force, and at the same time fluid under pressure is delivered to passages 28 and 29. This will cause the material in the central portion of the tubular blank to be forced upwardly into branch cavity 17, as seen successively in FIGURES 2 and 3.

From the very beginning of this operation, a portion of ram section 25 will be disposed within ram element 24, so that all portions of the tubular blank which remain in cavity 16 will be unable to move radially inward because of the presence of ram section 25. As blank 18 shortens, therefore, it will retain its inside diameter along the main run of the fitting. The metal which flows into branch cavity 17 will be forced against the sides of this cavity, assuming the diameter of the cavity.

In its final position, as seen in FIGURE 3, the material forced into cavity 17 will engage the top of this cavity, branch 29 of passage 28 still being disposed opposite cavity 17 at that time. Ram section 25 will be well within ram element 24.

After the forcing operation has been completed, the die sections 12 and 13 will be separated, ram elements 23 and 24 withdrawn and the fitting removed. At this time the cap portion 35 may be removed (FIGURE 5), leaving a completed branch fitting.

Various means may be used to create stops or solder cups for pipe ends to be connected to the fitting. One such method is seen in FIGURE 6 which shows the ends 36, 37 and 38 of the fitting enlarged by sizing to provide solder cups to the required depth. The controlled minimum diameter indicated at D in FIGURE 6 would still be retained in the central portion of the fitting. A particular value of the controlled inside diameter is that it may be used as a piloting diameter for the sizing tool used to increase the size of the ends.

While it will be apparent that the preferred embodiment of the invention disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. In a method for fabricating a wrought metal branch fitting, the steps of placing a tubular blank in the main cavity of a die having a main cavity and a branch cavity, placing a cylindrical member closed at one end in said tubular blank to prevent radially inward movement of the metal thereof, exerting oppositely directed forces on the ends of said tubular blank to force both ends of said tubular blank toward said branch, and simultaneously exerting fluid pressure on the inside of said blank adjacent said branch cavity through a passage leading from the other end of said cylindrical member, whereby said main cavity and blank ends will be free of fluid.

2. In an apparatus for making wrought metal branch fittings from a tubular blank of predetermined length, a die having a main cavity and a branch cavity, ram means comprising male and female ram elements, said male ram element having a main section slidably fitting within said main die cavity and a reduced section slidably fitting within said tubular blank, said reduced section of the male ram element being longer than the original predetermined length of said tubular blank, a shoulder between said main ram section and reduced ram section said shoulder being engageable with one end of said tu- 6 bular blank, a female ram element having an outer diam- References Cited eter slidably fitting within said main cavity and an inner diameter at one end thereof for slidably receiving that UNITED STATES PATENTS portion of the reduced male ram element section which 2,238,038 4/ 1941 Cornell 29-157 extends beyond said tubular blank, the annular end of 5 2,238,037 4/1941 Cornell 72 58 said female ram element engaging the other end of said 2,735,389 2/1956 Wurzberger 72-48 tubular blank, and a blind passage in said male ram ele- $762,326 9/1956 Burkhurt 72 '58 ment connectible to a source of pressurized fluid and having an opening in the vicinity of said branch cavity, RICHARD HERBST Pnmary Exammer' whereby said main die cavity and blank ends will be free 10 US. Cl. X.R. 

